Well tools



Sept. 15, 1964 c. M. SCHWAB 3,148,894

WELL TOOLS Filed June 26, 1958 2 SheetsSheet 1 Fi 3 INVENTOR Carl M. Schwo b Fig.2 BY W M F|g.l ATTORNEY Sept. 15, 1964 c. M. SCHWAB WELL TOOLS 2 Sheets-Sheet 2 Filed June 26, 1958 INVENTOR Carl M. Schwob BY M Fig.4

ATTORNEY United States Patent 3,148,894 WELL TOOLS Carl M. Schwab, Pasadena, Ten, assignor, by mesne assignments, to Otis Engineering Corporation, Dallas, Ten, a corporation of Delaware Filed lune 26, 1958, Ser. No. 744,722 2 Claims. (Cl. 285-3) This invention relates to well tools and more particularly to safety releasable joints for well pipes such as drill pipe, tubing or the like.

In the drilling or completion of a well it is often desirable to provide a safety joint in a well pipe such as the drill pipe or the tubing string whereby the upper portion of said well pipe can be parted or separated from the lower portion at a predetermined location in the event the lower end of the well pipe becomes stuck in the well. With drill pipe such sticking of the lower end of the pipe might occur because of a stuck drill, Whereas with tubing such sticking might occur because of a stuck packer. In addition, it may be desirable to part a tubing string at a point above a packer in order to circulate a weighted fluid such as drilling mud into the well to kill the well even though the packer may not be stuck.

Earlier devices involved the use of such mechanisms as shearable elements, low-friction threads, lefthand threads, or J-slots or similar elements. Such constructions are expensive to manufacture and uncertain of operation. Additionally, most involve the rotation of the well pipe in a certain direction. Withthe low friction thread design, the threads of the safety joint device must disengage rather than any of the other threaded joints by which the well pipe is joined together, presenting an uncertainty and often failure of successful operation. With the left-hand thread design, rotation of the well pipe is greatly restricted, as any rotation tending to tighten the threaded connection of the safety joint tends to loosen the other threaded joints of the well pipe. With the J-slot design, rotation of the pipe together with longitudinal movement of one section of the safety joint relative to another is generally used to release the joint, the result being that the permissible rotation of the well pipe is restricted to prevent inadvertent disconnection of the joint. Previously existing designs of safety joints also do not always admit of ready reconnection for the same reasons that their releasing operation is uncertain. I

In the event the well pipe becomes stuck at a joint at a point above a conventional safety joint, as, for example, through the setting up or solidifying of drilling mud, such conventional safety joint does not admit of disconnection because of the necessity of mechanical manipulation of the pipe and the upper part of such joint.

It is therefore an object of this invention to provide a releasable or safety joint for a well pipe wherein said joint can be easily and quickly disconnected at will, and without necessity of rotation of the well pipe or safety joint.

A further object is to provide a safety joint of the type described which, after being disconnected admits ofready and positive reconnection.

A still further object of the invention is to provide a safety joint which is releasable through the use of pump pressure applied to the well pipe and a simple lifting force on said pipe.

Another object is to provide a safety joint of the type described wherein said joint may be released even though the well pipe is stuck at a joint above the safety joint.

Still another object of the invention is to provide a safety joint which is capable of transmitting the torques customary with the Well pipe in which it is connected.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of devices constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURE 1 is a view, partly in section and partly in elevation, showing one form of the safety joint connected in a well pipe, the upper and lower sections of said joint being connected and locked in operative position.

FIGURE 2 is a View similar to FIGURE 1, showing the safety joint released and with its upper section being disconnected from its lower section.

FIGURE 3 is a view similar to FIGURE 2, showing the upper and lower sections of the safety joint reconnected and locked in place.

FIGURE 4 is a view, partly in section and partly in elevation, of a modified form of the invention, showing the upper and lower sections of said joint connected and locked but ready to be unlocked for disconnection.

FIGURE 5 is a cross-sectional view taken along the line 5-5 of FIGURE 4.

FIGURE 6 is a cross-sectional view taken along the line 66 of FIGURE 4.

Referring now to the drawings, particularly to FIG- URES 1 through 3, the numeral 10 indicates a releasable or safety joint including a tubular upper housing member 11 connected to the upper section of a well pipe or tubing string 12 and a tubular lower housing member 13 connected to a coupling 14 which is in turn connected to the lower section 12 of said well pipe.

The outer diameter 15 of the lower part of the upper housing member is reduced, and a plurality of vertical slits in through the wall of such reduced lower part extend upwardly from the lower end of said member to form a plurality of downwardly extending resilient collet fingers 17 having external bosses 18 at their lower ends.

The upper faces 13a of the bosses are inclined outwardly and downwardly at approximately forty-five degrees and the lower faces 18b of said bosses are downwardly and inwardly inclined at an angle of approximately thirty degrees from the vertical for a purpose to be hereinafter described.

The bore 19 of the upper part of the lower housing member is of an internal diameter approximating the outer diameter of the lower part of the upper housing member and receives such lower portion with a sliding fit. The collect fingers of the upper housing member may be flexed inwardly whereby the external bosses at the lower ends of said fingers may enter the bore of the lower housing member. An internal annular recess or groove 20 is provided in the lower housing section at a point such that, when the downwardly facing external annular shoulder 21 of the upper housing member, formed at the point of reduction of the outer diameter of said member, engages the upwardly facing shoulder 21a formed by the upper end of the lower housing member, the bosses of the collet fingers are disposed in horizontal alignment with said groove. The groove is of a configuration conforming to and designed to receive the bosses whereby said bosses may move outwardly into said groove under the resilient urging of the collet fingers, the fingers returning to their original or normally unfiexed position.

A tubular locking sleeve 22 is positioned in the lower part of the enlarged bore 19 of the lower housing member and is slidable longitudinally in said bore. Downward movement of the sleeve in the enlarged bore is limited by the engagement of a downwardly facing external shoulder 23 on the sleeve with an upwardly facing internal annular shoulder 24, at the lower end of such enlarged bore. The upper end of the locking sleeve is provided with a plurality of upstanding fingers or lugs 25 which enter into corresponding enlarged recesses 26 between the lower ends of the collet fingers of the upper housing member. The reresses cesses as are formed by lateral cuts 27 made into the sides of the lower ends of the collet fingers, and when the locking sleeve is moved to position its upstanding fingers within the spaces or recesses between the lower ends of the collet fingers, the lower ends of the collet fingers are prevented from moving inwardly and the bosses of said collet fingers are thus maintained in their outer positions. This result is accomplished because, as the collet fingers are flexed inwardly, their lower ends move closer together by virtue of the space between the fingers provided by the slits 16, and when the upstanding fingers or lugs of the locking sleeve are positioned in the recesses 26, they with the collet fingers form a complete circle and there is'no space for the collet fingers to flex inwardly into.

However, when the sleeve is moved downwardly to its lower position, its lugs or fingers are no longer engaged between the collet fingers of the upper housing section whereby said collet fingers may move inwardly. A shearable screw 23 is threaded through the wall of the lower housing member and enters an external annular groove 29 in the locking sleeve to releasably hold said sleeve in position with its lugs engaging in the recesses between the collet fingers.

An internal annular stop groove 3% is formed in the bore wall of the locking sleeve and is provided at its lower end with an abrupt upwardly facing lower annular stop shoulder An internal annular guide groove 32 is formed in the bore wall of the locking sleeve at a point spaced below the stop groove and has beveled upper and lower shoulders 33 and 34, respectively, defining its upper and lower ends.

An actuating plug 35 is inserted into the locking sleeve to move said locking sleeve from its upper collet finger engaging position to its lower position in the lower hous ing member, wherein the collet fingers are free to flex inwardly. The plug includes a packing mandrel 36 having a packing section or assembly 37 mounted exteriorly thereon and a body 38 threaded into the lower end of said packing mandrel. A plurality of longitudinal keys 39 are circumferentially spaced around the upper part of the body and are loosely retained on said body by an upwardly extending annular flange or lip 40 on the enlarged lower end 41 of the body and by a downwardly extending annular flange 42 on the lower end of the packing mandrel, whereby said keys may undergo limited lateral or radial movement on said body. A pair of springs 43 confined between each key and the body urge the keys to their outer limit of movement as defined by the engagement of said keys with the flanges. The inner limit of movement of the keys is fixed by the engagement of said keys with the body.

An outwardly projecting stop lug 44 is formed on the upper part of each key and is of a configuration corresponding with the stop groove 30 in the bore wall of the locking sleeve. The stop lugs are provided with downwardly facing abrupt stop shoulders 45 which are engage able with the upwardly facing stop shoulder 31 at the lower end of the stop groove. A guide lug 46 extends outwardly from the lower part of each key and has beveled upwardly and downwardly facing shoulders 47 and 48, respectively, the configuration of said guide lug corresponding to that of the guide groove 32.

A packing retainer cap 49 is threaded to the upper end of the packing mandrel and is provided with a downwardly facing shoulder 56 at its lower end to retain the packing assembly against upward movement on said mandrel. The packing assembly engages an upwardly facing external annular shoulder 51 on the mandrel to prevent said packing from moving downwardly on said mandrel.

The lateral projection of the guide and stop lugs from the keys is such that, when said keys are moved laterally inwardly against the force exerted by the springs 43, the plug may readily be inserted into the well pipe and lowered therein, the guide lug preventing the stop lug from entering recesses or engaging shoulders in the bore of said well pipe other than the recess 39 and shoulder 31 of the locking sleeve. When the lugs enter the correspond ing grooves in the sleeve, the keys are moved outwardly by the springs to their outer limit of movement and the stop shoulder of the stop lug engages the stop shoulder of the stop groove to stop further downward movement of the plug alone. However, fluid pressure applied to the upper end of the plug will then move the plug and the locking sleeve downwardly as will be more fullyexplained hereinafter. I

A plurality of downwardly extending lugs or splines 52 are welded or otherwise afiixed to the upper part of the upper housing member and extend downwardly along the exterior of the reduced portion of said upper housing member, and such splines slidably engage in a plurality of spline slots 52 of a configuration corresponding to that of the splines formed in the upper end of the lower housing member. The splines, by their entry into and engagement with the spline slots, cooperate with said slots to prevent rotation of the upper housing member relative to the lower housing member.

An 0-ring seal means 54 is provided on the exterior surface of the reduced portion of the upper housing member above the collet fingers and when said upper member is engaged with the lower housing member, said O-ring seals between the wall of the enlarged bore of the lower housing member and the upper housing member.

An O-ring seal means 55 mounted in a groove in the outer surface of the locking sleeve seals with the enlarged bore of the lower housing member, and the packing assembly 37 of the plug seals with the bore of the sleeve when said plug is installed in said sleeve. The O-ring seals and the packing assembly prevent fluid leakage between the interior and the exterior of the safety joint members. 7

In use, the locking sleeve is first installed in the lower housing member and is moved to its lower position therein. The lower end of the upper housing member is introduced into the upper end of the bore of the lower housing section, the beveled lower faces 18 of the bosses engaging the upper end of the bore wall of the lower housing member to cam said bosses inwardly, the collet fingers flexing inwardly to permit the bosses to enter such bore. The splines of the upper housing member are aligned with the spline slots of the lower housing member, and the upper housing member is lowered into said lower housing mem= her until the downwardly facing shoulder 21 of said upper member engages the upwardly facing shoulder 21a of the lower member. As the shoulders engage one another the bosses of the collet fingers move outwardly into the internal annular groove of the lower housing member.

The upstanding lugs of the locking sleeve are aligned with the recesses between the lower ends of the collet fingers, and the locking sleeve is moved upwardly until the lugs enter said recesses. The shearable screw is then installed in the lower housing section and projects into the groove 2? of the locking sleeve to hold said sleeve in locking position.

The safety joint is then connected between joints or sections of the well pipe as shown in FIGURE 1.

When it is desired to release the safety joint, the actuating plug is lowered into the well pipe by means of a flexible line and the usual flexible line tools until the plug reaches the locking sleeve, the guide lugs preventing the stop lugs of said plug from becoming lodged or stopped on any restriction or in any other recesses in said well pipe. When the plug enters the locking sleeve, the guide and stop lugs of the keys enter the corresponding recesses in the bore wall of said sleeve, whereby the downward movement of said plug is arrested. The flexible line tools may then be disengaged from the plug and removed from the well.

Fluid is introduced into the well pipe from its upper end, and pressure is applied by means of a pump (not shown). The fluid introduced is restrained above the plug by the packing assembly of said plug and by the O-ring seal means of the locking sleeve, whereby the pressure applied causes the plug and the locking sleeve to move downwardly in the lower housing member, moving the upstanding lugs on the upper end of said sleeve out of the recesses 26 between the collet fingers.

The collet fingers and the bosses are thus freed for inward movement. An upward pull is applied to the well pipe, and the upper faces of the bosses are cammed inwardly against the correspondingly beveled shoulder 56 defining the upper end of the annular groove in the lower housing member, said bosses thus being disengaged from said groove as shown in FIGURE 2. The upper section of the well pipe, together with the upper housing member of the safety joint, can then be removed from the well, leaving the lower housing member and the lower section of the well pipe in the Well.

In the event it is desired to reconnect the safety joint at a later time; as, for example, after loading the well with drilling mud above the lower housing member in order to kill the well, the upper section of the well pipe and the upper housing member are again lowered in the well. The beveled lower faces 26 of the bosses engage the upper end of the lower housing member and are cammed inwardly for entry into said lower member. The upper section of the well pipe is rotated until the splines and the spline'slots of the upper and lower housing members, respectively, are aligned, whereupon the upper housing member may be lowered to its original position in the lower housing member, the bosses of the collet fingers again moving outwardly into the groove of the lower housing member.

A locking bar or plug 57 having an outer diameter approximating the inner diameter of the well pipe is lowered or dropped into the well pipe, said bar coming to rest on the upper end of the actuating plug as shown in FIGURE 3. The locking bar thus prevents the inward movement of the collet fingers and so holds the bosses of said fingers locked in the groove of the lower housing member. An upward pull or a necessary rotational torque may be applied to the upper section of the well pipe to remove the entire string of said well pipe from the well.

It will thus be seen that a safety joint has been illustrated and described which, when connected, is capable of transmitting a torque in either direction, and which can be easily and quickly disconnected. It will further be seen that no rotation of the well pipe is necessary in releasing the safety joint, and that said joint may be released by the application of fluid pressure from the surface together with an upward pull on said well pipe.

It will be seen that the safety joint can be released even though the well pipe in which it is installed is stuck at a joint above said safety joint, as the pressure exerted to unlock said joint assists in the lifting of the upper section of said well pipe. It will also be seen that the safety joint cannot be inadvertently released or disconnected until positive steps have been taken to so release said joint. The safety joint, when engaged and locked, is capable of transmitting torques in either direction. It will additionally be seen that the safety joint can be easily and quickly reconnected and locked after initial unlocking and disconnection.

In FIGURES 4 through 6 a slightly modified form of the invention is illustrated, wherein the numeral 70 re fers generally to a safety joint which includes a tubular upper housing member 71 internally threaded to be connected to the upper section of a well pipe or string of drill pipe 72 and a tubular lower housing member 73 having a threaded pin 73a at its lower end by which it may be connected to the lower section of said well pipe.

The outer diameter of the lower part 74 of the upper housing member is reduced, and a plurality of vertical slits 75 extend upwardly through the wall of said lower part from the lower end of the member to form a plurality of depending resilient collet fingers 76. An external projection or boss 77 is provided at the lower end of each finger, the upper faces 78 of said bosses being slightly tapered downwardly and outwardly and the lower faces 79 0f saidbosses being tapered upwardly and outwardly at a greater angle.

The upper portion 80 of the bore of the lower housing member is enlarged and slidably receives the lower part of the upper housing member. An internal annular locking groove or recess 81 of a configuration corresponding to that of the bosses of the collet fingers is provided in the wall of the bore of the lower member at a position to receive the collet fingers of the upper housing member. The bosses 77 engage the bore wall of the lower member as they are inserted therein and are deflected inwardly for entry of the bosses into said bore, and when said bosses enter said recess, the collet fingers resiliently move the bosses back to their original or normal positions, and resiliently retain the bosses in the recess.

. A plurality of upwardly extending lugs or splines 82 are provided on the upper end of the lower housing member and enter into the spaces between a similar plurality of downwardly extending lugs or splines 83 on the upper part of the upper housing member. Downward movement of the upper housing member in the lower housing member is thus limited by engagement of the splines, and the relative rotation of the said members one to another is prevented. An O-ring seal means 83a is positioned in a recess in the upper part of the reduced lower section of the upper housing member and maintains a fluid seal between said upper housing member and the lower housing member.

A locking sleeve 84 is. longitudinally slidable in the lower part of the enlarged upper bore 80 of the lower housing member, downward movement of the sleeve in said lower member being limited by the engagement of the lower end of the sleeve with an internal annular upwardly facing shoulder 85 at the lower end of said enlarged bore. An O-ring seal means 86 is mounted in an external groove in the upper part of the locking sleeve to maintain a fluid seal between said sleeve and the wall of the enlarged bore of the lower housing member.

The lower inner ends of the collet fingers are relieved to provide recesses 87 in the fingers behind the bosses, and when the upper housing member is inserted into the lower housing member and the bosses of said collet fingers have entered the locking groove 81, the upper end of the locking sleeve may be moved upwardly into the recesses in inner lower ends of said fingers to abut or engage the interior relieved surfaces of the fingers and prevent inward movement of said fingers. The bosses of the collet fingers are thus retained in the locking groove to lock the upper and lower housing members together. When the sleeve is in its lower position in the lower housing member, its upper end is below the collet fingers, whereby said fingers are free for inward movement and the bosses may be withdrawn from the locking groove and the upper and lower members of the safety joint disconnected.

A plurality of shearable screws 88 are threaded through the wall of the lower housing member and extend into an annular groove 89 in the outer surface of the locking sleeve, whereby said sleeve is releasably held in its upper position locking the bosses of the collet fingers in the locking groove.

The bore 90 of the locking sleeve is smaller than that of the upper section of the well pipe, and an annular seating surface 91 is provided at the upper end of the bore of said sleeve for receiving a plug, such as the ball 92, whereby fluid pressure may be utilized to move the locking sleeve downwardly, as will be hereinafter explained.

In use, the locking sleeve is moved to its lower position in the lower housing member, and the upper and lower housing members'are connected, the collet fingers of the upper member being flexed inwardly so that the bosses aliases may enter the bore of said lower housing member. The upwardly extending lugs or splines 82 of the lower member are aligned for entry into the spaces between the downwardly extending lugs or splines 83 of the upper member, and the upper member is moved to its lower position in the lower member, the bosses of the collet fingers moving outwardly into the locking recess in the bore wall of the lower member. The locking sleeve is then moved upwardly to position its upper end in the recesses 87 between the lower ends of the collet fingers, and the shearable screws 88 are installed to hold said sleeve in position.

With the upper and lower housing members thus locked together, the safety joint is connected in a string of well pipe.

When it is desired to release the safety joint, a plug, such'as the ball 92 of a diameter approximating that of the well pipe, is lowered or dropped into said well pipe, sail plug coming to rest on the seating surface 92 at the upper end of the sleeve and sealing therewith as shown in FIGURE 4. Fluid pressure is then introduced into the upper end of the well pipe. The ball plug seals with the seat of the locking sleeve, and the Q-ring seal means 86 prevents leakage between the sleeve and the lower housing member, and the fluid pressure moves the locking sleeve downwardly to its lower position, shearing the shearable screws 33.

The upper end of the locking sleeve is thus moved downwardly below the lower ends of the collet fingers and said collet fingers are no longer held against inward movement. An upward pull on the upper section of the well pipe will then cause the upper housing member to be withdrawn from the lower member, the upper faces of the bosses camming the collet fingers inwardly by their engagement with the similarly tapered upper shoulder 3 defining the upper end of the locking groove 81. The upper section of the well pipe can then be withdrawn from the well.

When it is desired to reconnect the safety joint, as may be the case after the condition causing sticking of the well pipe has been corrected, the upper section of the well pipe and the upper housing member are again lowered into the well. The tapered lower faces '79 of the bosses of the collet fingers engage the upper end of the lower housing member, and the bosses and collet fingers are cammed inwardly as the upper member is lowered into said lower member. The upper section of the well pipe is rotated to align the spaces between the splines or lugs of said upper member with the splines or lugs of said lower member until the upper and lower members are completely telescoped as shown in FIGURE 4. With the members so telescoped, the collect bosses again move outwardly into the locking groove of the lower member. A locking bar or sleeve (not shown) of a diameter approximating that of the bore of the upper section of the well pipe is lowered or dropped through the string of well pipe and comes to rest on the ball 92. The locking bar, which may be similar to the locking bar 57 shown in FIGURE 3, serves as a backing lock or stop to prevent the inward ilexure of the collet fingers, thereby locking the upper and lower housing members together. The entire well pipe may then be elevated and removed from the well.

If a source of fluid under pressure is not available for releasing either form of the safety joint, it is possible to release said joints by means of wire line operated jarring tools or by dropping a common weighted sinker bar (not shown) into the well pipe to deliver a downward blow to the actuating plug 35 shown in FIGURE 2 or to the ball 92 shown in FIGURE 4 in order to fracture the shearable screws and so move the locking sleeve downwardly from its upper locking position. "The sinker bar can then be withdrawn from the well pipe by the usual wire line tools before the safety joint housing members are disconnected.

It will be seen that a safety joint has been illustrated and r 8 V described in this modified form of the invention which can be easily and quickly disconnected at will, and which can be similarly reconnected. No rotation of the parts of the safety joint relative to one another is necessary to release their connection, said joint being released by a simple upward pull on the upper section of the attached well pipe after the locking sleeve has been moved to its lower unlocking position. The locking sleeve of the safety joint may be moved to its unlocking position by means of fluid pressure or by means of a common weighted sinker bar, or wire line operated jarring tools.

It will also be seen that this modified form of the safety joint can be released even though the stuck joint in the well pipe is located above the safety joint, as the fluid pressureutilized to unlock said safety joint also assists in the lifting of the upper section of said well pipe.

It will further be seen that this form of the safety joint cannot be inadvertently released, as disconnection is impossible until definite steps have been taken to unlock said joint.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by, Letters Patent is:

1. A releasable joint for well pipe including: a lower tubular member having its bore wall provided with an internal annular locking recess; an upper tubular member having a reduced lower portion telescoping into the upper end of said lower member; a plurality of dependent resilient fingers on the lower end of said reduced portion; out' wardly projecting boss means on the lower ends of said fingers adapted to engage in said internal locking recess, the fingers of said upper member being flexible laterally inwardly from normal initial position to permit said bosses to be slidably inserted into the bore of said lower tubular member, said fingers resiliently returning to their normal position to dispose said outwardly projecting bosses in said locking recess when said lower portion of the upper tubular member is moved downwardly into the lower tubular member a sufiicient distance to position said bosses in alignment with said locking recess; a locking sleeve slidable longitudinally in said lower tubular member between an upper position and a lower position; means carried by said locking sleeve engaging and holding said fingers against inward flexing to retain the bosses thereon engaged in said locking recess of the lower member, said means on said locking sleeve permitting inward flexing of said fingers when said locking sleeve is in said lower position; means releasably holding said locking sleeve in its upper position and releasable to permit said sleeve to move downwardly to its lower position; said locking sleeve having a bore therethrough of a diameter approximating that of said upper member; said locking sleeve having a landing recess with an upwardly facing stop shoulder formed in its bore wall; a plug tool lowerable into the bore of said sleeve and including a body; a stop key on said body movable laterally from an outer projecting position to an inner retracted position and having a downwardly facing stop shoulder; resilient means on said body engaging and biasing said key to projecting position disposed to engage in said landing recess, whereby said stop shoulder of said key engages said stop shoulder of said sleeve to support said plug tool in said sleeve; packing means on said body engaging and sealing with the bore wall of said locking sleeve; packing means on said locking sleeve sealing with the bore wall of said lower member; and means on said upper and lower members coengageable to prevent relative rotation between said members about their longitudinal axes.

2. A releasable joint for well pipes including: a lower tubular member having its bore wall provided with an internal annular locking recess; an upper tubular member having a reduced lower portion telescoping into the upper end of said lower member; a plurality of dependent resilient fingers on the lower end of said reduced portion; outwardly projecting boss means on the lower ends of said fingers adapted to engage in said internal locking recess, the fingers of said upper member being flexible laterally inwardly from normal initial position to permit said boss means to be slidably inserted into the bore of said lower tubular member, said fingers resiliently returning to their normal position to dispose said outwardly projecting boss means in said locking recess when said lower portion of the upper tubular member is moved downwardly into the lower tubular member a sufiicient distance to position said boss means in alignment with said locking recess; a locking sleeve slidable longitudinally in said lower tubular member between an upper position and a lower position; means carried by said locking sleeve engaging and holding said fingers against inward flexing to retain the boss means thereon engaged in said locking recess of the lower member when said locking sleeve is in said upper position, said means carried by said locking sleeve permitting inward flexing of said fingers when said locking sleeve is in said lower position; means carried by said upper tubular member engageable with said locking means when said locking means is in said upper position preventing upward movement of said locking means out of locking engagement with said fingers; means releasably holding said locking sleeve in its upper position and releasable to permit said sleeve to move downwardly to its lower position; closure means lowerable through said well pipe to closing engagement with said locking sleeve to close the bore of said locking sleeve whereby fluid pressure may be applied to said closure means and locking sleeve to release said sleeve and move the same downwardly to its lower posi tion; said boss means on said fingers having beveled lower faces disposed to engage the upper inner surface of said lower tubular member on subsequent lowering of said upper member into said lower member whereby said boss means and said fingers are cammed inwardly for entry into said lower member; said upper member being movable downwardly into said lower member until said boss means reengage in said locking recess; a locking bar lowerable into said joint into engagement with said closure means and having an outer surface engageable by said fingers whereby said fingers are held in expanded position to relock'said upper and lower tubular members together; and means on said upper and lower members coengageable to prevent relative rotation between'said members about their longitudinal axes.

References Zited in the file of this patent UNITED STATES PATENTS 2,248,305 Rasmussen July 8, 1941 2,798,559 Fredd July 9, 1957 2,843,399 Arterbury et al July 15, 1958 2,862,560 Bostock et al Dec. 2, 1958 2,862,564 Bostock Dec. 2, 1958 2,901,045 Schramm Aug. 25, 1959 

1. A RELEASABLE JOINT FOR WELL PIPE INCLUDING: A LOWER TUBULAR MEMBER HAVING ITS BORE WALL PROVIDED WITH AN INTERNAL ANNULAR LOCKING RECESS; AN UPPER TUBULAR MEMBER HAVING A REDUCED LOWER PORTION TELESCOPING INTO THE UPPER END OF SAID LOWER MEMBER; A PLURALITY OF DEPENDENT RESILIENT FINGERS ON THE LOWER END OF SAID REDUCED PORTION; OUTWARDLY PROJECTING BOSS MEANS ON THE LOWER ENDS OF SAID FINGERS ADAPTED TO ENGAGE IN SAID INTERNAL LOCKING RECESS, THE FINGERS OF SAID UPPER MEMBER BEING FLEXIBLE LATERALLY INWARDLY FROM NORMAL INITIAL POSITION TO PERMIT SAID BOSSES TO BE SLIDABLY INSERTED INTO THE BORE OF SAID LOWER TUBULAR MEMBER, SAID FINGERS RESILIENTLY RETURNING TO THEIR NORMAL POSITION TO DISPOSE SAID OUTWARDLY PROJECTING BOSSES IN SAID LOCKING RECESS WHEN SAID LOWER PORTION OF THE UPPER TUBULAR MEMBER IS MOVED DOWNWARDLY INTO THE LOWER TUBULAR MEMBER A SUFFICIENT DISTANCE TO POSITION SAID BOSSES IN ALIGNMENT WITH SAID LOCKING RECESS; A LOCKING SLEEVE SLIDABLE LONGITUDINALLY IN SAID LOWER TUBULAR MEMBER BETWEEN AN UPPER POSITION AND A LOWER POSITION; MEANS CARRIED BY SAID LOCKING SLEEVE ENGAGING AND HOLDING SAID FINGERS AGAINST INWARD FLEXING TO RETAIN THE BOSSES THEREON ENGAGED IN SAID LOCKING RECESS OF THE LOWER MEMBER, SAID MEANS ON SAID LOCKING SLEEVE PERMITTING INWARD FLEXING OF SAID FINGERS WHEN SAID LOCKING SLEEVE IS IN SAID LOWER POSITION; MEANS RELEASABLY HOLDING SAID LOCKING SLEEVE IN ITS UPPER POSITION AND RELEASABLE TO PERMIT SAID SLEEVE TO MOVE DOWNWARDLY TO ITS LOWER POSITION; SAID LOCKING SLEEVE HAVING A BORE THERETHROUGH OF A DIAMETER APPROXIMATING THAT OF SAID UPPER MEMBER; SAID LOCKING SLEEVE HAVING A LANDING RECESS WITH AN UPWARDLY FACING STOP SHOULDER FORMED IN ITS BORE WALL; A PLUG TOOL LOWERABLE INTO THE BORE OF SAID SLEEVE AND INCLUDING A BODY; A STOP KEY ON SAID BODY MOVABLE LATERALLY FROM AN OUTER PROJECTING POSITION TO AN INNER RETRACTED POSITION AND HAVING A DOWNWARDLY FACING STOP SHOULDER; RESILIENT MEANS ON SAID BODY ENGAGING AND BIASING SAID KEY TO PROJECTING POSITION DIS~ POSED TO ENGAGE IN SAID LANDING RECESS, WHEREBY SAID STOP SHOULDER OF SAID KEY ENGAGES SAID STOP SHOULDER OF SAID SLEEVE TO SUPPORT SAID PLUG TOOL IN SAID SLEEVE; PACKING MEANS ON SAID BODY ENGAGING AND SEALING WITH THE BORE WALL OF SAID LOCKING SLEEVE; PACKING MEANS ON SAID LOCKING SLEEVE SEALING WITH THE BORE WALL OF SAID LOWER MEMBER; AND MEANS ON SAID UPPER AND LOWER MEMBERS COENGAGEABLE TO PREVENT RELATIVE ROTATION BETWEEN SAID MEMBERS ABOUT THEIR LONGITUDINAL AXES. 